<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <button>按钮</button>
    <input type="text" value="输入内容">
    <script>
        //   需求： 点击按钮， 禁用， 修改表单内容 
        let btn = document.querySelector('button');
        let input = document.querySelector('input');

        btn.onclick = function () {
            btn.disabled = true;
            // this.disabled = true;
            // btn.disabled = true;
            input.value = '点击了'
        }
        //  点击 恢复   
        
    </script>
</body>

</html>